<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false">
  {{ deflang }}
  <span class="caret"></span>
</a>
<ul class="dropdown-menu" role="menu">
  <li ng-repeat="lang in langs">
    <a ng-click="changeLang(lang)">{{lang}}</a>
  </li>
</ul>
